I'm not sure about NEC rules, but here's what my OEC requires in ontario, canada.
-Forget about 2" conduit, that's for 200A panels using 3/0 wire.
-Never use aluminum unless its underground USCI90 triplex cable.
-If you really want conduit, use 1 1/4" and #3 CU with #6 ground.
-To save money...